Here's an interesting experiment. Take a novice user, place them in front of a Linux distro (in this case Ubuntu Hardy Heron), and see how they get on with basic tasks. But will these "12:00 flashers" (you know, people who's VCRs constantly flash "12:00" because they've not bothered to figure out how to set the time) help change Linux and make it easier to use?
I've long thought that part of the reason why Linux hasn't made much progress in terms of picking up novice users is that many distros suffers from a geek overload. Now there's no doubt that things have improved dramatically over the past couple of years and distros such as Ubuntu are especially user friendly for novices, but I've hit plenty of tar pits myself to know that Linux doesn't equal plain sailing. I've come to expect Linux distros to work well most of the time, but I've also grown to accept that any problems that I encounter can take a lot of time and effort to solve. I'm happy to hit the forums and do a lot of Google legwork, but many aren't.
Enter the novice user. This person isn't interested in reading release notes, manuals, forums and such. These kinds of users just want things to work. If you want to test how user friendly something is, don't give it to someone who knows how to use it, give it to someone who doesn't! As these users encounter roadblocks, take notes and see if anything can be done to make the experience easier or less hassle. However, you have to be careful not to confuse user friendliness with over-simplification, and there's a fine line between the two. Also, let's not forget that if you ask a Windows user for UI tips, what you end up with are usually suggestions for making Linux look and feel more like Windows. I don't think it would help anyone if Linux distros tried to be Windows clones.
Linux suffers a couple of disadvantages that Windows and Mac OS don't. First, a Linux distro link Ubuntu isn't an OS but more a complete PC environment. Not only do you have the core OS, but you also have a raft of applications on offer, far more than Windows or Mac has to offer. This means that everyone contributing to a distro has to work at getting the UI right. That's a lot of work, and getting consistency would take a lot of effort. In fact, quite a few of the criticisms leveled at Ubuntu in the article come down to specific applications rather than the OS itself.
The other disadvantage is that while most encounter Windows or Mac on a system set up by the OEM, most people coming to Linux have to install and configure the OS themselves. To you or me that might seem trivial, but for a lot of people out there the idea of installing an OS is a daunting one. Just as most people don't expect to have to fit an engine in their car, most don't expect to have to install an OS. This means that developers have to compensate for this by making the install as easy as possible. Ubuntu is one distro that has a very streamlined install process that most people (even "12:00 flasher") should be able to handle most of the time.
I'm pretty sure that a distro like Ubuntu would cater for a good 80% of users, but the key is for the OS to be properly set up first and to have things like Flash player set up in advanced. So, if you know your way around Linux, do a novice a favor and offer to set them up with a dual-boot distro so they can take it for a proper test drive.